The genus Neisseria includes two gram-negative species of pyogenic cocci that are pathogenic for man, and that have no other known reservoir: the meningococcus (Neisseria meningitidis) and the gonococcus (Neisseria gonorrhoeae). A number of non-pathogenic species also inhabit the upper respiratory tract of humans and may be easily confused with meningococci. Meningococcal meningitis was recognized as a contagious disease early in the 19th century and is especially prevalent among military personnel. The causative agent of meningococcal meningitis is Neisseria meningitidis.
Neisseria gonorrhoeae is one of the main causes of epidemic sexually transmitted disease and is prevalent in the United States. Infection with Neisseria gonorrhoeae causes many common symptoms including urethritis, cervicitis, and proctitis. In addition, chronic infection with Neisseria gonorrhoeae can cause pelvic inflammatory disease.
Meningococci have polysaccharide-containing capsules. Gonococcis may also possess capsules, but the exact chemical composition of such a capsule is unknown. In addition, both gonococci and meningococci may have pili which play a role in virulence.
Meningococci and gonococci are difficult to cultivate and require special techniques to grow the organisms from body fluids. In addition, selective culture medium, (for example, Thayer-Martin medium) and growth in 3-10% carbon dioxide at approximately 35.degree. C. is required to maximize the culture of organisms.
In addition to the difficult cultivation, the gonococcus and meningococcus detection by immunoassay suffers a lack of sensitivity and specificity. This appears to be due to the cross reaction between various other pathogens and non-pathogenic microorganisms often found in the same clinical specimens.
Oligonucleotides for the amplification of nucleic acid for detection of Neisseria have been described. Bikenmeyer and Armstrong, J. Clin. Microbiol. 30:3089-3094 (1992), describe probe sets for use in the ligase chain reaction directed to the Opa and pilin genes of Neisseria gonorrhoeae. Kristiansen et al. Lancet 340:1432-1434 (1992) describe primers directed to an insertion element referred to as IS1106 for amplification and detection of Neisseria meningitidis. McLaughlin et al., Mol. and Cell Probes 7:7-17 (1993) describe primers for use in the polymerase chain reaction directed to the 16S-23S rRNA internal transcribed spacer and a set of primers directed to a subregion of the 16S rRNA of Neisseria meningitidis. Probes for the detection of rRNA or rDNA sequences of Neisseria gonorrhoeae and/or Neisseria meningitidis have been described by Granato and Franz J. Clin. Microbiol. 28:944-948, (1990), Wolff, U.S. Pat. No. 5,173,401 (Dec. 22, 1992), Rossau and Van Heuverswijn, European Patent Application Publication No. 0 337 896, Hogan et al. PCT/US87/03009, and Barns et al., U.S. Pat. No. 5,217,862 (Jun. 8, 1993).